Straws of uniform diameter adapted to be inserted into a sealed container for liquid beverages to enable the user to drink from the container are well-known. The known straws that have been commonly used are often cylindrical and of uniform diameter throughout their length including both the front end serving as a piercing means to the basal end serving as a mouthpiece. A straw having such a uniform diameter is usually attached to the container's outer side diagonally thereof after the straw has been put into the associated package.
When such a uniform diameter straw pierces the container, a circular hole is created through the wall of the container corresponding in diameter to that of the straw. This leaves no gap between the peripheral edge of said hole and the outer surface of said the, so that insufficient ventilation occurs between the interior and the exterior of the container to facilitate smooth drinking from the container.
Another inconvenience of such uniform diameter straws, particularly those designed to be attached to the container's outer side, is that their length is so limited that the straw could be lost into the container during drinking, if the user carelessly lets it fall into the container.
To overcome the first-mentioned inconvenience, it has been proposed to form the intermediate portion of the straw with at least one groove extending longitudinally of the straw to provide the desired ventilation between the interior and the exterior of the container.
Also, to eliminate the last-mentioned inconvenience, it is also known to provide the basal end of the straw serving as the mouthpiece with a stopper adapted to prevent the straw from falling into the container.
Of these well-known straws which are claimed to be improved as above mentioned, the first-mentioned one provided with at least one groove is, theoretically, certainly advantageous because a gap should be provided by said groove between the straw and the hole through which the straw is inserted into the container and the gap should assure the desired ventilation between the interior and the exterior of the container. However, it has been found from practical use of such straws that the straw readily adapts itself to said hole formed through the container wall due to the properties of the synthetic resin from which the straw is made and, as a consequence, makes it difficult to establish the desired ventilation.
The last-mentioned straw construction provided with the stopper around the basal end of the straw serving as the mouthpiece to prevent the straw from falling into the container is still inconvenient. Not only is it inconvenient in that it does not necessarily assure the ventilation but also because the diameter of the basal end serving as the mouthpiece is considerably larger than the diameter of the front end serving as the piercing means preventing a plurality of such straws from being packaged in parallel relationship to each other during a packaging process conducted in an automatic packaging machine or the like. Thus, automation of the packaging operation has encountered a serious problem since the smooth feeding or movement of these straws essential to automation cannot be assured.
In view of these problems which have been encountered in the use of prior art straws, a first objective of the present invention is to assure that, after a sealed container for liquid beverages has been pierced by the front end of the straw, there is reliably created between the edge of the hole formed as a result of said piercing and the outer surface of the straw extending through the hole a sufficient gap to establish the necessary ventilation between the interior and the exterior of the container. A second objective of the present invention is to provide a novel straw so configured that a plurality of them can be smoothly fed into and passed through an automatic packaging machine or the like to package them in a close-pack parallel arrangement.